Ocean ans and liberties

[Tony Wilding]

the ocean class and liberty both american built late 1941, , both welded, original hull design for both was a british empire class , i believe ss dorrington court. The ocean remained basicaly unchanged from original design of the empire ship, flush deck 3 island, 2 hatches fwd, 1 abaft the bridge, 2 aft of midships,, the liberty hull was much altered, one solitary accomodation block just aft of amidships, 3 hatches fwd,, 2 aft, 99 percent of liberties were welded, as were all oceans, empires were rivetted, we hear many reports ,see photos of liberties broken in half, allways at same position, fwd of bridge, huge cracks in decks, around the hatch corners, some even sunk from fractures. Have never heard of a ocean class having these problems, it was stated liberties were stiff ships, when ehe replacement victories were built the main frames were further apart, and they were less stiff. Any theories why liberties cracked and oceans did not ?.

[robpage]

The welding was a poor quality , there are tales that in the Vee groove the Welders placed unwelded rods and seamed over them , true or not the welding technology and standards were poor

[John Arton]

Tony
Search U tube etc for "The Last of the Liberties". This gives the full account of why they cracked.
Basically
Square hatch corners
Incorrect steel, the Liberties that cracked were all operating in cold waters and the standard of steel used, although o.k. for normal waters, quickly became brittle when these ships went into cold climates.
If you can find it, it's a really good video.
Record for building one Liberty ship, 4 days
rgds
JA

[alf corbyn]

I was always told the welding was done by students who were paid by length of weld

[Captain Kong]

I remember the ESSO Hibernia, 256,000 dwt, she cracked all around outward bound on her maiden voyage in ballast, towed stern first into Lisbon dry dock. the welds were just welding rods stuffed in the joints and welded over.
Built on the Tyne. with the ESSO Northumbria who was no better. she was a heap.
.
There was a big difference to the Esso Caledonia and the Esso Ulidia, all four identical plans, they were built in Harlands in Belfast. far better built. I sailed on all four.
.
As John stated the welds on the Liberty ships at first were square and then when they rounded the joints at the coamings the cracks stopped.
Cheers
Brian

[Tony Wilding]

They also put a band of rivetted plates around the hull from aft end of no1 hatch to fwd end of no 5 hatch, as far as i know rge Oceans needed none of these modifications, both built from the end of 1941, one big difference was all the Oceans built by same Shipyard.

[Tony Wilding]

hi Brian, which Yard built the first 2 ?. amazing they got away with it, suppose once it is seamed over no way to check, untill the cracks appear. no wonder we lost our Shipbuilding. i have a photo of a T2 Tanker, launched the day befor, the next morning the Bow and Stern high in the air, a clean break just aft of the Bridge, maybe the stresses of launching weakened Her, She was ok when tied up, afloat less than 12 hours. looked like she had been neatly cut in half, was put back together, was a few damaged Liberties bought by the Italians , , half Ships, eventually rejoined to a Stern or Bow of a different Liberty, then of course the Jumboised Liberties in Japan. they look odd.

[Captain Kong]

Hi Tony, the ESSO Hibernia and ESSO Northumbria were built at Swan Hunters on the Tyne and the Esso Caledonia and Esso Ulidia were built in Harlands in Belfast.
These were 1,117 feet in length, the fore deck from the bridge to the bow was 965 feet. You could place four T2s on the fore deck Beam 170 feet. 256,000 dw tons,
If I remember rightly.Here is a view of that class.

[Tony Wilding]

not the sort of ships you want faulty welds on, unbelievable it was not picked up on while building. Extremely scary also.

[John Arton]

Re. Liberty Ships
Welding was a process that was introduced into ship building during WW2 with the advent of the Liberty ships that were desperately needed to keep the U.K. going.
Many welders were recruited for this new ship building system, including women. As welding itself was a relatively new technique the science behind and its possible faults and failures was also new.
Investigations have absolved the welders engaged in building the Liberties of the responsibility for the cracking of them.
The two main causes were.
1. Square hatch corners. This introduces stress concentration points. In a riveted ship if a crack starts in one plate it cannot travel through into the next plate as there is a physical break in the riveted joint. Welding two plates together effectively turns them into one so if a crack develops in one plate there is nothing to stop it transmitting through the next plate and so on.
2. Quality of steel. If the liberties had been riveted the steel used would have been fine, however the steel used, when taken into cold climates, became brittle so cracks propagated very quickly. The Liberties that cracked in half were all operating in cold waters in the high Northern latitudes.
Examination of the welds showed that they were stress fractures and not nucleation. The difference between a stress fracture and one caused by nucleation are easily visible with the naked eye. As a temporary measure curved inserts were riveted into the hatch corners at main deck level and straps riveted across the deck by the hatch corners. Curved inserts at hatch corners will be found in every modern welded vessel.
Re. Esso super tankers etc. I was talking to a guy who investigated the Derbyshire and what he found may have some bearing on the Esso Tyne built ships.
At that time the Government of the day had told U.K. shipyards to consolidate and following shipbuilding techniques used in Japanese and Scandinavian yards.
This introduced the concept of building ships in large blocks, under cover if possible, then welding them together on the slipway or in the dock.
This is fine if you have the technology and the equipment to do this but most of the U.K. yards did not and remember the Esso tankers were built on a sloping slipway which is obviously more difficult to get the blocks lined up and joined to thousands of an inch, whereas if I am correct, the H and W ships would have been built in the dry dock. Building in a flat dock is obviously easier to get alignment correct than on a slip way and also removes any of the launching stresses induced when going down a slipway.
A further problem with the Derbyshire was that the original drawings were in feet and inches and then converted into metric for plate cutting and block building, leading to misalignment of framing etc. due to the conversion factor used to convert feet and inches to metric.
In our first house one of my neighbours had been a plater/blacksmith in the Tees yard that built the Bridge OBO's and he openly admitted to the fact that they could not always get the blocks to line up correctly so they would just throw in welding rods to fill the gap and then weld over them.
It was not the quality of the workforce that made these ships such disaster's, more the government rush to get U.K. shipyards to modernise without giving them the dosh to invest in the necessary new technology required to turn around from traditional ship building methods to the new methods used by the foreign competitors.
The result is there for all of us to see, a rapid decline in ship building in the U.K. as the world could see that large ships built in the U.K. were pretty rubbish so no owner was willing to place orders. A and P with there SD's were very successful but they were building "small" ships up to around 25,000 tons which is a totally different ball game to 100-200,000 tonners.
rgds
JA